A gas leak at an oil recycling company forced about 4,000 workers to evacuate nearby office buildings for six hours Monday, sending one person to the hospital, authorities said.
Firefighters who arrived at Heartland Petroleum LLC saw a gas cloud over the company, said Battalion Chief David Whiting.
The cloud, which quickly dissipated, was a mixture of hydrogen and hydrogen sulfide, based on information provided by the company, Whiting said.
Because hydrogen is flammable, emergency responders ordered the evacuation of nearby offices.
Heartland Petroleum is part of a large industrial development area near Port Columbus International Airport. Workers at a DSW Inc. shoe warehouse were among those sent home.
Two people were treated at the scene for minor breathing problems, and a third who complained of the same malady was sent to a hospital, Whiting said. No additional information on the patient was released.
The cause of the gas leak remained under investigation, but the problem appeared to be related to a faulty gasket on one of the oil tanks, Whiting said.
Brad Lambert, chief financial officer at Heartland Petroleum, said the problem started with a power outage early in the morning. When power was restored, it caused a surge in a computer system and blew the gasket, he said.
The company hoped to resume operations by the end of the week, Lambert said.
"Safety, of course, will be our No. 1 priority," he said.
The U.S. Occupational Safety and Health Administration had a team at the site. The agency has six months to complete an investigation, said David Wilson, an assistant area director in Columbus.
The gas leak was reported about 8 a.m., and the main road in front of the complex was closed for six hours as a precaution.
The leak disrupted work at an office building across the street that belongs to the Ohio Department of Job and Family Services. The building is home to the agency's main unemployment benefits call center.
Because of the evacuation, calls Monday were handled by other agency offices in the region and delays were common, spokesman Brian Harter said. Normal operations were expected to resume Tuesday.